UP10-16APMBU/LC, 115V Pump, w/ Auto Adapt & Line Cord (1-1/4" Union)

Purchased this to replace a discontinued timer model, which froze up. This was a recommended replacement model and no one in town had one in stock and figured if I had to order one, I would look for a better price and order it myself. SupplyHouse.com provided very good customer service and responded to email questions; phone purchase and shipping was quick. The only complaints I have are with Grundfos. They picture book instructions are terrible and left me guessing on the placement of the temperature sensor. After a lot of looking around, I was able to find a written manual online. Secondly, mind had the Union connection, which was very easy to change out. The unit does not come with replacement washers and I could not find them in town. Told they had to be ordered from Grundfos...ridiculous, or purchase new connections that come with them (not at $30 plus, just to get washers). Luckily, my 11 year old ones were able to be reused.

This is a very nice pump mechanically - excellent fit and finish, quiet, energy efficient, and in theory presents a world of options. However there are some flaws in the programming software: - AUTO mode -> I have not used this extensively but I've read the white paper and it basically builds up a schedule of events. This probably works pretty well if you dont WFH and leave/return/shower etc at regular hours. Otherwise it's just not smart enough and it'll just run 24/7 or not when it needs to. They state this in the literature, so that's not a knock as much as it is something you should be aware of. - Temperature Mode -> Herein lies the issue. In theory all this needs to do is learn via the external sensor the hottest temperature your hot water gets to, and then compare that to the sensor in the housing, and keep it in a range. It will run for 15 mins initially to learn that temp. However, overnight it seems to gradually heat to a lower and lower range so that come morning the water in the loop is tepid at best. The cycles also seem to be extremely short - so short that I doubt it is heating the entire loop and I think it's likely not even heating the brass nipple under the external sensor to actual discharge temperature. The flaw here is whatever hysteresis algorithm they use should not be averaging down within 24 hours, nobody is changing their hot water temperature that often - and they should be cycling the pump long enough to ensure that whatever their external sensor is mounted to heat soaks. It does neither. I solved the TEMP mode issue by putting the pump on a Eve smart plug and setting it to power cycle every morning before we get up for 1 minute/on-off. When the pump first turns on it runs for 15 minutes to establish a baseline, so it resets whatever unfortunate adjustments the pump made overnight. You could also just place it into 24/7 mode and DIY the timing. Overall it's a mixed bag and the cheaper models (backordered) should be considered.